Living soils

If you’ve ever tried growing your own vegetables and fruits, you can understand why chemical solutions to pests, weeds and diseases are an attractive option. For five years, I had an allotment near my home in Twickenham. I was busy, and the kids were young, and so any time I spent there tended to be spent fighting a losing battle with weeds, whose growth was relentless. And then, when I finally got things to grow, there was always an insect or fungus that seemed to fancy a bit of my crop. It was frustrating. Now imagine you have 40 hectares of vines to look after, and your financial future depends on getting good yields of healthy grapes. It’s not hard to understand the allure of agrochemicals.



The problem, though? We’re only just beginning to realize that vineyard soils aren’t simply a growth medium for vines. A vineyard is what is known as an agroecosystem, with lots of organisms living together. Good soils are full of life, and this soil microlife turns out to be pretty important. Spray herbicides and rely on chemical disease and pest control, and you lose a lot of this diversity, and with it any hope of achieving a natural balance. Like a drug addict, you are then increasingly reliant on these chemical solutions, and this isn’t sustainable.


This was illustrated to me very clearly on a visit to Stellenbosch producer Waterkloof. I was taken round the property, and shown two adjoining vineyards. One had been farmed conventionally, with herbicides used to control the weeds. The soil was rock hard, like concrete. Just next door, a few metres away, was another vineyard with the same soil type, but these soils had been farmed using a specialized form of organic viticulture called biodynamics, for a number of years, and had never been treated with herbicides. The soil felt completely different: it was friable and loose, and looked a lot more alive than the first.


Biodynamics is still niche in South Africa, but interest in it is on the increase, along with regular organic farming. Both organics and biodynamics share in common a focus on healthy, living soils; biodynamics goes a little further in that it treats the farm as a whole system, and as well as farming organically with composts, and no herbicides or pesticides, there are also a range of special preparations that can be used to treat soil, plants and compost, and the timing of certain operations is linked with a special calendar that takes account of the movement of the stars.


Waterkloof are one of the leading proponents of biodynamics in South Africa, and have replaced their tractors with a team of Percheron horses, which they use to cultivate the soil. The advantage? They have much less impact on the soil than tractors, reducing compaction. As well as implementing biodynamics, they also use smart science to reduce potential problems, such as establishing native vegetation areas to act as refuges for potentially beneficial insects and using biological rather than chemical control of pests. They also use chicken and sheep to help with pest and weed issues, and keep cows – their manure is an ideal base for biodynamic composts.


Another standard-bearer for biodynamics is Stellenbosch producer Johan Reyneke. On my last visit I spent some time with him in the vineyard: he currently farms his 40 hectares this way. This will soon expand, though, because half of the neighbouring farm has come up for sale. Reyneke are buying it, which means they’ll have 80 hectares of estate vineyards. The deal is that when they buy this slice of the neighbour’s farm, they are also allowed to farm the remaining 40 hectares of vines and have the grapes for no extra cost. This would leave Johan farming 120 hectares, making it one of the globe’s largest biodynamically farmed vineyards.


But farming a large vineyard using biodynamics is quite a challenge. One of the key decisions for biodynamic farmers is whether or not to work the soil. If you leave a permanent sward and just mow occasionally, this is good for soil microlife, but bad for yield. In this part of Stellenbosch this would give him yields of 4 tons/hectare. With soil cultivation, he can double the yield because of the lack of competition for soil nutrients and water, so it would seem to be the sensible thing to do. An added advantage of cultivation is that it disturbs the surface vine roots and forces the vine to send roots further down.


But cultivation can be bad for soil life, as it’s bringing a layer of soil up to the surface and thus disturbs the microbial balance. Also, discs used to cultivate the soil can create a hard pan just below where they reach. Johan has recently been looking at older texts written by farmers who worked before the widespread availability of chemical solutions, and is getting lots of ideas for ways of preserving the soil microlife while not taking an unnecessary yield hit. It will be interesting to see which route he finally chooses.


Why is soil life important? It’s becoming clear that the vine roots are interacting with bacteria and fungi in the soil in interesting ways. Recent research has shown that the interplay between soil microbes and roots can increase drought tolerance of the vine and also help with grape quality. The soil microbes also play an important role in making soil minerals available to the vine roots. Smart viticulture is as much about farming soils as it is about farming vines.


Another interesting biodynamic grower is Elgin Ridge. Brian and Marion Smith are British ex-pats who have committed to running their wine farm using biodynamics, and their vineyards have never been treated chemically. As well as vines, they have a herd of Dexter cows and a Percheron horse. Pest control is achieved by a flock of ducks, and with careful management, the whole farm acts as a self-sustaining system. Are their wines better for this biodynamic approach? It’s impossible to say for sure, but the likelihood is that they are, and that is certainly the experience of many growers in Europe (where biodynamics is better established) who have made the switch from conventional to biodynamic.


As I walked around the vineyards with Johan Reyneke, I saw a group of workers doing the painstaking and back breaking task of manually removing a persistent weed, Italian rye grass. A quick treatment of herbicide would be much quicker, but Johan isn’t interested. And although he spends half his vineyard budget on labour, he’s happy to be giving people jobs, and says that it is cheaper for him to farm biodynamically because he doesn’t have to pay for agrochemicals. As he points out, cow shit is free.

By: Jamie Goode for Wines of South Africa


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